getting zziplib to work in php5

I've been trying to get zip functionality working with php5, after installing php5, php5-cli and whatever those things depend on via Synaptic. From the description of php5-cli though, zip support is already suppose to be compiled with it. Yet i get errors like:

Fatal error: Call to undefined function zip_open() in /path/file.php on line 79

still. I also installed zziplib-bin and libzzip-dev via Synaptic... any suggestions? Thanks.